Developing analytical instrumentation with high detection sensitivity and selectivity is crucial to our abilities to solve meaningful analytical problems. Among the more sensitive analytical techniques are those employing gas chromatography/mass spectrometric analysis (GC/MS), where GC-retention time, mass, and intensity are molecule selective, and therefore useful for molecular identification. For a number of years, researchers have sought to expand on MS detection methods by using a monochromatic electron beam of varying energy to scan an unknown analyte. In a process called dissociative electron capture, electrons of specific energies are captured to produce ions of characteristic masses that can be detected as a fragment ion with MS. In effect, the resonance energy spectrum—ion yield as a function of electron energy—creates an additional molecular characteristic to supplement those produced with traditional GC/MS.
An electron monochromator (EM) may be coupled to a mass spectrometer (MS) to create an EM-MS analytical tool for the investigation of electrophilic compounds. For example, an EM-MS may provide a powerful tool for molecular identification of compounds contained in complex matrices, such as environmental samples. However, before this tool can realize its full potential, it will be necessary to create a library of resonance energy scans from standards of the molecules for which EM-MS offers a practical means of detection. Unfortunately, the number of such standards is very large and not all of the compounds are commercially available, making this library difficult to construct.